After rebooting the system (twice) I still do not see the service and get the same message. I am pasting the screenshot of the service manager, I see only scheduler services.
I'm not sure what's happened in that case. Please download http://www.enterprisedb.com/postgresql-904-installers-win32 (that's the PG 9.0.4 installer) and run it. It should upgrade/reinstall the Postgres Plus Standard Server database component.